Envelope power supply calibration of a multi-mode radio frequency power amplifier

ABSTRACT

The present disclosure relates to envelope power supply calibration of a multi-mode RF power amplifier (PA) to ensure adequate headroom when operating using one of multiple communications modes. The communications modes may include multiple modulation modes, a half-duplex mode, a full-duplex mode, or any combination thereof. As such, each communications mode may have specific peak-to-average power and linearity requirements for the multi-mode RF PA. As a result, each communications mode may have corresponding envelope power supply headroom requirements. The calibration may include determining a saturation operating constraint based on calibration data obtained during saturated operation of the multi-mode RF PA. During operation of the multi-mode RF PA, the envelope power supply may be restricted to provide a minimum allowable magnitude based on an RF signal level of the multi-mode RF PA, the communications mode, and the saturation operating constraint to provide adequate headroom.

This application is a Divisional of U.S. patent application Ser. No.13/019,077, filed Feb. 1, 2011, which claims the benefit of U.S.provisional patent application No. 61/300,089, filed Feb. 1, 2010, thedisclosures of which are incorporated herein by reference in theirentireties.

FIELD OF THE DISCLOSURE

Embodiments of the present disclosure relate to radio frequency (RF)power amplifier (PA) circuitry, which may be used in RF communicationssystems.

BACKGROUND OF THE DISCLOSURE

As wireless communications technologies evolve, wireless communicationssystems become increasingly sophisticated. As such, wirelesscommunications protocols continue to expand and change to take advantageof the technological evolution. As a result, to maximize flexibility,many wireless communications devices must be capable of supporting anynumber of wireless communications protocols, including protocols thatoperate using different communications modes, such as a half-duplex modeor a full-duplex mode, and including protocols that operate usingdifferent frequency bands. Further, the different communications modesmay include different types of RF modulation modes, each of which mayhave certain performance requirements, such as specific out-of-bandemissions requirements or symbol differentiation requirements. In thisregard, certain requirements may mandate operation in a linear mode.Other requirements may be less stringent that may allow operation in anon-linear mode to increase efficiency. Wireless communications devicesthat support such wireless communications protocols may be referred toas multi-mode multi-band communications devices.

A half-duplex mode is a two-way mode of operation, in which a firsttransceiver communicates with a second transceiver; however, only onetransceiver transmits at a time. Therefore, the transmitter and receiverin such a transceiver do not operate simultaneously. For example,certain telemetry systems operate in a send-then-wait-for-reply manner.Many time division duplex (TDD) systems, such as certain Global Systemfor Mobile communications (GSM) systems, operate using the half-duplexmode. A full-duplex mode is a simultaneous two-way mode of operation, inwhich a first transceiver communicates with a second transceiver andboth transceivers may transmit simultaneously; therefore, thetransmitter and receiver in such a transceiver must be capable ofoperating simultaneously. In a full-duplex transceiver, signals from thetransmitter must not interfere with signals received by the receiver;therefore, transmitted signals are at transmit frequencies that aredifferent from received signals, which are at receive frequencies. Manyfrequency division duplex (FDD) systems, such as certain wideband codedivision multiple access (WCDMA) systems or certain long term evolution(LTE) systems, operate using a full-duplex mode. A linear mode relatesto RF signals that include amplitude modulation (AM). A non-linear moderelates to RF signals that do not include AM. Since non-linear mode RFsignals do not include AM, devices that amplify such signals may beallowed to operate in saturation. Devices that amplify linear mode RFsignals may operate with some level of saturation, but must be able toretain AM characteristics sufficient for proper operation.

As a result of the differences between full duplex operation and halfduplex operation, RF front-end circuitry may need specific circuitry foreach mode. Additionally, support of multiple frequency bands may requirespecific circuitry for each frequency band or for certain groupings offrequency bands. FIG. 1 shows a traditional multi-mode multi-bandcommunications device 10 according to the prior art. The traditionalmulti-mode multi-band communications device 10 includes a traditionalmulti-mode multi-band transceiver 12, traditional multi-mode multi-bandPA circuitry 14, traditional multi-mode multi-band front-end aggregationcircuitry 16, and an antenna 18. The traditional multi-mode multi-bandPA circuitry 14 includes a first traditional PA 20, a second traditionalPA 22, and up to and including an N^(TH) traditional PA 24.

The traditional multi-mode multi-band transceiver 12 may select one ofmultiple communications modes, which may include a half-duplex transmitmode, a half-duplex receive mode, a full-duplex mode, a linear mode, anon-linear mode, multiple RF modulation modes, or any combinationthereof. Further, the traditional multi-mode multi-band transceiver 12may select one of multiple frequency bands. The traditional multi-modemulti-band transceiver 12 provides an aggregation control signal ACS tothe traditional multi-mode multi-band front-end aggregation circuitry 16based on the selected mode and the selected frequency band. Thetraditional multi-mode multi-band front-end aggregation circuitry 16 mayinclude various RF components, including RF switches; RF filters, suchas bandpass filters, harmonic filters, and duplexers; RF amplifiers,such as low noise amplifiers (LNAs); impedance matching circuitry; thelike; or any combination thereof. In this regard, routing of RF receivesignals and RF transmit signals through the RF components may be basedon the selected mode and the selected frequency band as directed by theaggregation control signal ACS.

The first traditional PA 20 may receive and amplify a first traditionalRF transmit signal FTTX from the traditional multi-mode multi-bandtransceiver 12 to provide a first traditional amplified RF transmitsignal FTATX to the antenna 18 via the traditional multi-mode multi-bandfront-end aggregation circuitry 16. The second traditional PA 22 mayreceive and amplify a second traditional RF transmit signal STTX fromthe traditional multi-mode multi-band transceiver 12 to provide a secondtraditional RF amplified transmit signal STATX to the antenna 18 via thetraditional multi-mode multi-band front-end aggregation circuitry 16.The N^(TH) traditional PA 24 may receive an amplify an N^(TH)traditional RF transmit signal NTTX from the traditional multi-modemulti-band transceiver 12 to provide an N^(TH) traditional RF amplifiedtransmit signal NTATX to the antenna 18 via the traditional multi-modemulti-band front-end aggregation circuitry 16.

The traditional multi-mode multi-band transceiver 12 may receive a firstRF receive signal FRX, a second RF receive signal SRX, and up to andincluding an M^(TH) RF receive signal MRX from the antenna 18 via thetraditional multi-mode multi-band front-end aggregation circuitry 16.Each of the RF receive signals FRX, SRX, MRX may be associated with atleast one selected mode, at least one selected frequency band, or both.Similarly, each of the traditional RF transmit signals FTTX, STTX, NTTXand corresponding traditional amplified RF transmit signals FTATX,STATX, NTATX may be associated with at least one selected mode, at leastone selected frequency band, or both.

Portable wireless communications devices are typically battery powered,need to be relatively small, and have low cost. As such, to minimizesize, cost, and power consumption, multi-mode multi-band RF circuitry insuch a device needs to be as simple, small, and efficient as ispractical. Thus, there is a need for multi-mode multi-band RF circuitryin a multi-mode multi-band communications device that is low cost,small, simple, and efficient that meets performance requirements.

SUMMARY OF THE EMBODIMENTS

The present disclosure relates to envelope power supply calibration of amulti-mode RF power amplifier (PA) to ensure adequate headroom whenoperating using one of multiple communications modes. The communicationsmodes may include multiple modulation modes, a half-duplex mode, afull-duplex mode, or any combination thereof. As such, eachcommunications mode may have specific peak-to-average power andlinearity requirements for the multi-mode RF PA. As a result, eachcommunications mode may have corresponding envelope power supplyheadroom requirements. The calibration may include determining asaturation operating constraint based on calibration data obtainedduring saturated operation of the multi-mode RF PA at different envelopepower supply levels. During operation of the multi-mode RF PA, theenvelope power supply may be restricted to provide a minimum allowablemagnitude based on an RF signal level of the multi-mode RF PA, thecommunications mode, and the saturation operating constraint to provideadequate headroom.

By performing the calibration during saturated operation, a maximumpower capability of the multi-mode RF PA at each envelope power supplylevel may be determined. When combined with communications mode specificheadroom requirements, the minimum allowable magnitude of the envelopepower supply may be determined. As a result, calibrations during linearoperation of the multi-mode RF PA may be unnecessary, therebysimplifying calibration requirements. Since efficiency of the multi-modeRF PA may be maximized when the headroom of the envelope power supply isminimized, controlling the envelope power supply to minimize theheadroom of the envelope power supply while meeting headroomrequirements may optimize the efficiency of the multi-mode RF PA. Themulti-mode RF PA may be a multi-mode multi-band RF PA capable ofamplifying RF signals in multiple frequency bands. As such, acalibration may be necessary for each frequency band or for certaingroupings of frequency bands. However, by performing each calibrationduring saturated operation, numerous calibrations during linearoperations may be avoided, thereby simplifying calibration requirements.

By performing a calibration during saturated operation, temperaturecompensation of the headroom requirements may be simplified. In oneembodiment of the multi-mode RF PA, temperature compensation of amagnitude of the envelope power supply is based on only a singlevolts-per-degree slope value. The calibration of the multi-mode RF PAmay be performed under different conditions, such as during amanufacturing and testing process of the multi-mode RF PA; after themulti-mode RF PA is integrated into a module; after the multi-mode RF PAis integrated into an end product, such as a cell phone; the like; orany combination thereof. The calibration of the multi-mode RF PA mayinclude sweeping the envelope power supply across its operating range.In an alternate embodiment of the multi-mode RF PA, instead ofcalibrating the multi-mode RF PA directly, a surrogate RF PA may becalibrated instead. As such, the calibration data may be obtained duringsaturated operation of the surrogate RF PA at different envelope powersupply levels. Typically, the multi-mode RF PA would have similarcharacteristics to those of the surrogate RF PA. For example, themulti-mode RF PA and the surrogate RF PA may be from the samesemiconductor wafer. In general, the calibration data is obtained duringsaturated operation of a calibration RF PA, which may be the multi-modeRF PA or the surrogate RF PA.

Those skilled in the art will appreciate the scope of the presentdisclosure and realize additional aspects thereof after reading thefollowing detailed description of the preferred embodiments inassociation with the accompanying drawing figures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The accompanying drawing figures incorporated in and forming a part ofthis specification illustrate several aspects of the disclosure, andtogether with the description serve to explain the principles of thedisclosure.

FIG. 1 shows a traditional multi-mode multi-band communications deviceaccording to the prior art.

FIG. 2 shows RF communications circuitry according to one embodiment ofthe RF communications circuitry.

FIG. 3 shows RF communications circuitry according to an alternateembodiment of the RF communications circuitry.

FIG. 4 shows RF communications circuitry according to an additionalembodiment of the RF communications circuitry.

FIG. 5 shows RF communications circuitry according to another embodimentof the RF communications circuitry.

FIG. 6 shows RF communications circuitry according to a furtherembodiment of the RF communications circuitry.

FIG. 7 shows RF communications circuitry according to one embodiment ofthe RF communications circuitry.

FIG. 8 shows details of RF power amplifier (PA) circuitry illustrated inFIG. 5 according to one embodiment of the RF PA circuitry.

FIG. 9 shows details of the RF PA circuitry illustrated in FIG. 5according to an alternate embodiment of the RF PA circuitry.

FIG. 10 is a graph showing a saturated load line and a linear load lineassociated with a first RF PA and an envelope power supply signalillustrated in FIG. 5 according to one embodiment of the first RF PA andthe envelope power supply signal.

FIG. 11 is a graph showing a saturated operating characteristicassociated with the first RF PA and the envelope power supply signalillustrated in FIG. 5 according to one embodiment of the first RF PA andthe envelope power supply signal.

FIG. 12 is a graph showing the saturated operating characteristic, alinear operating characteristic, a first modulation specific operatingcharacteristic, and a second modulation specific operatingcharacteristic associated with the first RF PA and the envelope powersupply signal illustrated in FIG. 5 according to one embodiment of thefirst RF PA and the envelope power supply signal.

FIG. 13 shows a calibration configuration for obtaining firstcalibration data at different envelope power supply levels according toone embodiment of the present disclosure.

FIG. 14 shows a calibration configuration for obtaining the firstcalibration data and second calibration data according to an alternateembodiment of the present disclosure.

FIG. 15 shows a calibration configuration for obtaining the firstcalibration data and the second calibration data according to anadditional embodiment of the present disclosure.

FIG. 16 illustrates a process for obtaining the first calibration dataaccording to one embodiment of the present disclosure.

FIG. 17 illustrates a process for obtaining the second calibration dataaccording to one embodiment of the present disclosure.

FIG. 18 illustrates a process for determining an offset and a modulationback-off of a calibration RF PA according to one embodiment of thepresent disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments set forth below represent the necessary information toenable those skilled in the art to practice the disclosure andillustrate the best mode of practicing the disclosure. Upon reading thefollowing description in light of the accompanying drawing figures,those skilled in the art will understand the concepts of the disclosureand will recognize applications of these concepts not particularlyaddressed herein. It should be understood that these concepts andapplications fall within the scope of the disclosure and theaccompanying claims.

The present disclosure relates to envelope power supply calibration of amulti-mode RF power amplifier (PA) to ensure adequate headroom whenoperating using one of multiple communications modes. The communicationsmodes may include multiple modulation modes, a half-duplex mode, afull-duplex mode, or any combination thereof. As such, eachcommunications mode may have specific peak-to-average power andlinearity requirements for the multi-mode RF PA. As a result, eachcommunications mode may have corresponding envelope power supplyheadroom requirements. The calibration may include determining asaturation operating constraint based on calibration data obtainedduring saturated operation of the multi-mode RF PA at different envelopepower supply levels. During operation of the multi-mode RF PA, theenvelope power supply may be restricted to provide a minimum allowablemagnitude based on an RF signal level of the multi-mode RF PA, thecommunications mode, and the saturation operating constraint to provideadequate headroom.

By performing the calibration during saturated operation, a maximumpower capability of the multi-mode RF PA at each envelope power supplylevel may be determined. When combined with communications mode specificheadroom requirements, the minimum allowable magnitude of the envelopepower supply may be determined. As a result, calibrations during linearoperation of the multi-mode RF PA may be unnecessary, therebysimplifying calibration requirements. Since efficiency of the multi-modeRF PA may be maximized when the headroom of the envelope power supply isminimized, controlling the envelope power supply to minimize theheadroom of the envelope power supply while meeting headroomrequirements may optimize the efficiency of the multi-mode RF PA. Themulti-mode RF PA may be a multi-mode multi-band RF PA capable ofamplifying RF signals in multiple frequency bands. As such, acalibration may be necessary for each frequency band or for certaingroupings of frequency bands. However, by performing each calibrationduring saturated operation, numerous calibrations during linearoperations may be avoided, thereby simplifying calibration requirements.

By performing a calibration during saturated operation, temperaturecompensation of the headroom requirements may be simplified. In oneembodiment of the multi-mode RF PA, temperature compensation of amagnitude of the envelope power supply is based on only a singlevolts-per-degree slope value. The calibration of the multi-mode RF PAmay be performed under different conditions, such as during amanufacturing and testing process of the multi-mode RF PA; after themulti-mode RF PA is integrated into a module; after the multi-mode RF PAis integrated into an end product, such as a cell phone; the like; orany combination thereof. The calibration of the multi-mode RF PA mayinclude sweeping the envelope power supply across its operating range.In an alternate embodiment of the multi-mode RF PA, instead ofcalibrating the multi-mode RF PA directly, a surrogate RF PA may becalibrated instead. As such, the calibration data may be obtained duringsaturated operation of the surrogate RF PA at different envelope powersupply levels. Typically, the multi-mode RF PA would have similarcharacteristics to those of the surrogate RF PA. For example, themulti-mode RF PA and the surrogate RF PA may be from the samesemiconductor wafer. In general, the calibration data is obtained duringsaturated operation of a calibration RF PA, which may be the multi-modeRF PA or the surrogate RF PA.

FIG. 2 shows RF communications circuitry 26 according to one embodimentof the RF communications circuitry 26. The RF communications circuitry26 includes RF modulation and control circuitry 28, RF PA circuitry 30,and a DC-DC converter 32. The RF modulation and control circuitry 28provides an envelope control signal ECS to the DC-DC converter 32 andprovides an RF input signal RFI to the RF PA circuitry 30. The DC-DCconverter 32 provides a bias power supply signal BPS and an envelopepower supply signal EPS to the RF PA circuitry 30. The envelope powersupply signal EPS may be based on the envelope control signal ECS. Assuch, a magnitude of the envelope power supply signal EPS may becontrolled by the RF modulation and control circuitry 28 via theenvelope control signal ECS. The RF PA circuitry 30 may receive andamplify the RF input signal RFI to provide an RF output signal RFO. Theenvelope power supply signal EPS may provide power for amplification ofthe RF input signal RFI to the RF PA circuitry 30. The RF PA circuitry30 may use the bias power supply signal BPS to provide biasing ofamplifying elements in the RF PA circuitry 30.

In a first embodiment of the RF communications circuitry 26, the RFcommunications circuitry 26 is multi-mode RF communications circuitry26. As such, the RF communications circuitry 26 may operate usingmultiple communications modes. In this regard, the RF modulation andcontrol circuitry 28 may be multi-mode RF modulation and controlcircuitry 28 and the RF PA circuitry 30 may be multi-mode RF PAcircuitry 30. In a second embodiment of the RF communications circuitry26, the RF communications circuitry 26 is multi-band RF communicationscircuitry 26. As such, the RF communications circuitry 26 may operateusing multiple RF communications bands. In this regard, the RFmodulation and control circuitry 28 may be multi-band RF modulation andcontrol circuitry 28 and the RF PA circuitry 30 may be multi-band RF PAcircuitry 30. In a third embodiment of the RF communications circuitry26, the RF communications circuitry 26 is multi-mode multi-band RFcommunications circuitry 26. As such, the RF communications circuitry 26may operate using multiple communications modes, multiple RFcommunications bands, or both. In this regard, the RF modulation andcontrol circuitry 28 may be multi-mode multi-band RF modulation andcontrol circuitry 28 and the RF PA circuitry 30 may be multi-modemulti-band RF PA circuitry 30.

The communications modes may be associated with any number of differentcommunications protocols, such as Global System of Mobile communications(GSM), Gaussian Minimum Shift Keying (GMSK), Enhanced Data rates for GSMEvolution (EDGE), Wideband Code Division Multiple Access (WCDMA), andLong Term Evolution (LTE). The GSM and GMSK protocols do not includeamplitude modulation (AM). As such, the GSM and GMSK protocols may beassociated with a non-linear mode. Further, the GSM and GMSK protocolsmay be associated with a saturated mode. The EDGE, WCDMA, and LTEprotocols may include AM. As such, the EDGE, WCDMA, and LTE protocolsmay by associated with a linear mode.

FIG. 3 shows RF communications circuitry 26 according to an alternateembodiment of the RF communications circuitry 26. The RF communicationscircuitry 26 illustrated in FIG. 3 is similar to the RF communicationscircuitry 26 illustrated in FIG. 2, except in the RF communicationscircuitry 26 illustrated in FIG. 3, the RF modulation and controlcircuitry 28 provides a first RF input signal FRFI, a second RF inputsignal SRFI, and a PA configuration control signal PCC to the RF PAcircuitry 30. The RF PA circuitry 30 may receive and amplify the firstRF input signal FRFI to provide a first RF output signal FRFO. Theenvelope power supply signal EPS may provide power for amplification ofthe first RF input signal FRFI to the RF PA circuitry 30. The RF PAcircuitry 30 may receive and amplify the second RF input signal SRFI toprovide a second RF output signal SRFO. The envelope power supply signalEPS may provide power for amplification of the second RF output signalSRFO to the RF PA circuitry 30. Certain configurations of the RF PAcircuitry 30 may be based on the PA configuration control signal PCC. Asa result, the RF modulation and control circuitry 28 may control suchconfigurations of the RF PA circuitry 30.

FIG. 4 shows RF communications circuitry 26 according to an additionalembodiment of the RF communications circuitry 26. The RF communicationscircuitry 26 illustrated in FIG. 4 is similar to the RF communicationscircuitry 26 illustrated in FIG. 3, except in the RF communicationscircuitry 26 illustrated in FIG. 4, the RF PA circuitry 30 does notprovide the first RF output signal FRFO and the second RF output signalSRFO. Instead, the RF PA circuitry 30 may provide one of a first alphaRF transmit signal FATX, a second alpha RF transmit signal SATX, and upto and including a P^(TH) alpha RF transmit signal PATX based onreceiving and amplifying the first RF input signal FRFI. Similarly, theRF PA circuitry 30 may provide one of a first beta RF transmit signalFBTX, a second beta RF transmit signal SBTX, and up to and including aQ^(TH) beta RF transmit signal QBTX based on receiving and amplifyingthe second RF input signal SRFI. The one of the transmit signals FATX.SATX, PATX, FBTX, SBTX, QBTX that is selected may be based on the PAconfiguration control signal PCC.

FIG. 5 shows RF communications circuitry 26 according to anotherembodiment of the RF communications circuitry 26. The RF communicationscircuitry 26 illustrated in FIG. 5 shows details of the RF modulationand control circuitry 28 and the RF PA circuitry 30 illustrated in FIG.4. Additionally, the RF communications circuitry 26 illustrated in FIG.5 further includes transceiver circuitry 34, front-end aggregationcircuitry 36, and the antenna 18. The transceiver circuitry 34 includesdown-conversion circuitry 38, baseband processing circuitry 40, and theRF modulation and control circuitry 28, which includes control circuitry42 and RF modulation circuitry 44. The RF PA circuitry 30 includes afirst transmit path 46 and a second transmit path 48. The first transmitpath 46 includes a first RF PA 50 and alpha switching circuitry 52. Thesecond transmit path 48 includes a second RF PA 54 and beta switchingcircuitry 56. The front-end aggregation circuitry 36 is coupled to theantenna 18. The control circuitry 42 provides the aggregation controlsignal ACS to the front-end aggregation circuitry 36. Configuration ofthe front-end aggregation circuitry 36 may be based on the aggregationcontrol signal ACS. As such, configuration of the front-end aggregationcircuitry 36 may be controlled by the control circuitry 42 via theaggregation control signal ACS.

The control circuitry 42 provides the envelope control signal ECS to theDC-DC converter 32 and provides the PA configuration control signal PCCto the RF PA circuitry 30. As such, the control circuitry 42 may controlconfiguration of the RF PA circuitry 30 via the PA configuration controlsignal PCC and may control a magnitude of the envelope power supplysignal EPS via the envelope control signal ECS. The control circuitry 42may select one of multiple communications modes, which may include afirst half-duplex transmit mode, a first half-duplex receive mode, asecond half-duplex transmit mode, a second half-duplex receive mode, afirst full-duplex mode, a second full-duplex mode, at least one linearmode, at least one non-linear mode, multiple RF modulation modes, or anycombination thereof. Further, the control circuitry 42 may select one ofmultiple frequency bands. The control circuitry 42 may provide theaggregation control signal ACS to the front-end aggregation circuitry 36based on the selected mode and the selected frequency band. Thefront-end aggregation circuitry 36 may include various RF components,including RF switches; RF filters, such as bandpass filters, harmonicfilters, and duplexers; RF amplifiers, such as low noise amplifiers(LNAs); impedance matching circuitry; the like; or any combinationthereof. In this regard, routing of RF receive signals and RF transmitsignals through the RF components may be based on the selected mode andthe selected frequency band as directed by the aggregation controlsignal ACS.

The down-conversion circuitry 38 may receive the first RF receive signalFRX, the second RF receive signal SRX, and up to and including theM^(TH) RF receive signal MRX from the antenna 18 via the front-endaggregation circuitry 36. Each of the RF receive signals FRX, SRX, MRXmay be associated with at least one selected mode, at least one selectedfrequency band, or both. The down-conversion circuitry 38 maydown-convert any of the RF receive signals FRX, SRX, MRX to basebandreceive signals, which may be forwarded to the baseband processingcircuitry 40 for processing. The baseband processing circuitry 40 mayprovide baseband transmit signals to the RF modulation circuitry 44,which may RF modulate the baseband transmit signals to provide the firstRF input signal FRFI or the second RF input signal SRFI to the first RFPA 50 or the second RF PA 54, respectively, depending on the selectedcommunications mode.

The first RF PA 50 may receive and amplify the first RF input signalFRFI to provide the first RF output signal FRFO to the alpha switchingcircuitry 52. Similarly, the second RF PA 54 may receive and amplify thesecond RF input signal SRFI to provide the second RF output signal SRFOto the beta switching circuitry 56. The first RF PA 50 and the second RFPA 54 may receive the envelope power supply signal EPS, which mayprovide power for amplification of the first RF input signal FRFI andthe second RF input signal SRFI, respectively. The alpha switchingcircuitry 52 may forward the first RF output signal FRFO to provide oneof the alpha transmit signals FATX, SATX, PATX to the antenna 18 via thefront-end aggregation circuitry 36, depending on the selectedcommunications mode based on the PA configuration control signal PCC.Similarly, the beta switching circuitry 56 may forward the second RFoutput signal SRFO to provide one of the beta transmit signals FBTX,SBTX, QBTX to the antenna 18 via the front-end aggregation circuitry 36,depending on the selected communications mode based on the PAconfiguration control signal PCC.

FIG. 6 shows RF communications circuitry 26 according to a furtherembodiment of the RF communications circuitry 26. The RF communicationscircuitry 26 illustrated in FIG. 6 is similar to the RF communicationscircuitry 26 illustrated in FIG. 5, except in the RF communicationscircuitry 26 illustrated in FIG. 6, the transceiver circuitry 34includes a control circuitry digital communications interface (DCI) 58,the RF PA circuitry 30 includes a PA DCI 60, the DC-DC converter 32includes a DC-DC converter DCI 62, and the front-end aggregationcircuitry 36 includes an aggregation circuitry DCI 64. The DCIs 58, 60,62, 64 are coupled to one another using a digital communications bus 66.In the digital communications bus 66 illustrated in FIG. 6, the digitalcommunications bus 66 is a uni-directional bus in which the controlcircuitry DCI 58 may communicate information to the PA DCI 60, the DC-DCconverter DCI 62, the aggregation circuitry DCI 64, or any combinationthereof. As such, the control circuitry 42 may provide the envelopecontrol signal ECS via the control circuitry DCI 58 to the DC-DCconverter 32 via the DC-DC converter DCI 62. Similarly, the controlcircuitry 42 may provide the aggregation control signal ACS via thecontrol circuitry DCI 58 to the front-end aggregation circuitry 36 viathe aggregation circuitry DCI 64. Additionally, the control circuitry 42may provide the PA configuration control signal PCC via the controlcircuitry DCI 58 to the RF PA circuitry 30 via the PA DCI 60.

FIG. 7 shows RF communications circuitry 26 according to one embodimentof the RF communications circuitry 26. The RF communications circuitry26 illustrated in FIG. 7 is similar to the RF communications circuitry26 illustrated in FIG. 6, except in the RF communications circuitry 26illustrated in FIG. 7, the digital communications bus 66 is abi-directional bus and each of the DCIs 58, 60, 62, 64 is capable ofreceiving or transmitting information. In alternate embodiments of theRF communications circuitry 26, any or all of the DCIs 58, 60, 62, 64may be uni-directional and any or all of the DCIs 58, 60, 62, 64 may bebi-directional.

FIG. 8 shows details of the RF PA circuitry 30 illustrated in FIG. 5according to one embodiment of the RF PA circuitry 30. Specifically,FIG. 8 shows details of the alpha switching circuitry 52 and the betaswitching circuitry 56 according to one embodiment of the alphaswitching circuitry 52 and the beta switching circuitry 56. The alphaswitching circuitry 52 includes an alpha RF switch 68 and a first alphaharmonic filter 70. The beta switching circuitry 56 includes a beta RFswitch 72 and a first beta harmonic filter 74. Configuration of thealpha RF switch 68 and the beta RF switch 72 may be based on the PAconfiguration control signal PCC. In one communications mode, such as analpha half-duplex transmit mode, an alpha saturated mode, or an alphanon-linear mode, the alpha RF switch 68 is configured to forward thefirst RF output signal FRFO to provide the first alpha RF transmitsignal FATX via the first alpha harmonic filter 70. In anothercommunications mode, such as an alpha full-duplex mode or an alphalinear mode, the alpha RF switch 68 is configured to forward the firstRF output signal FRFO to provide any of the second alpha RF transmitsignal SATX through the P^(TH) alpha RF transmit signal PATX. When aspecific RF band is selected, the alpha RF switch 68 may be configuredto provide a corresponding selected one of the second alpha RF transmitsignal SATX through the P^(TH) alpha RF transmit signal PATX.

In one communications mode, such as a beta half-duplex transmit mode, abeta saturated mode, or a beta non-linear mode, the beta RF switch 72 isconfigured to forward the second RF output signal SRFO to provide thefirst beta RF transmit signal FBTX via the first beta harmonic filter74. In another communications mode, such as a beta full-duplex mode or abeta linear mode, the beta RF switch 72 is configured to forward thesecond RF output signal SRFO to provide any of the second beta RFtransmit signal SBTX through the Q^(TH) beta RF transmit signal QBTX.When a specific RF band is selected, beta RF switch 72 may be configuredto provide a corresponding selected one of the second beta RF transmitsignal SBTX through the Q^(TH) beta RF transmit signal QBTX. The firstalpha harmonic filter 70 may be used to filter out harmonics of an RFcarrier in the first RF output signal FRFO. The first beta harmonicfilter 74 may be used to filter out harmonics of an RF carrier in thesecond RF output signal SRFO.

FIG. 9 shows details of the RF PA circuitry 30 illustrated in FIG. 5according to an alternate embodiment of the RF PA circuitry 30.Specifically, FIG. 9 shows details of the alpha switching circuitry 52and the beta switching circuitry 56 according to an alternate embodimentof the alpha switching circuitry 52 and the beta switching circuitry 56.The alpha switching circuitry 52 includes the alpha RF switch 68, thefirst alpha harmonic filter 70, and a second alpha harmonic filter 76.The beta switching circuitry 56 includes the beta RF switch 72, thefirst beta harmonic filter 74, and a second beta harmonic filter 78.Configuration of the alpha RF switch 68 and the beta RF switch 72 may bebased on the PA configuration control signal PCC. In one communicationsmode, such as a first alpha half-duplex transmit mode, a first alphasaturated mode, or a first alpha non-linear mode, the alpha RF switch 68is configured to forward the first RF output signal FRFO to provide thefirst alpha RF transmit signal FATX via the first alpha harmonic filter70. In another communications mode, such as an second alpha half-duplextransmit mode, a second alpha saturated mode, or a second alphanon-linear mode, the alpha RF switch 68 is configured to forward thefirst RF output signal FRFO to provide the second alpha RF transmitsignal SATX via the second alpha harmonic filter 76. In an alternatecommunications mode, such as an alpha full-duplex mode or an alphalinear mode, the alpha RF switch 68 is configured to forward the firstRF output signal FRFO to provide any of a third alpha RF transmit signalTATX through the P^(TH) alpha RF transmit signal PATX. When a specificRF band is selected, the alpha RF switch 68 may be configured to providea corresponding selected one of the third alpha RF transmit signal TATXthrough the P^(TH) alpha RF transmit signal PATX.

In one communications mode, such as a first beta half-duplex transmitmode, a first beta saturated mode, or a first beta non-linear mode, thebeta RF switch 72 is configured to forward the second RF output signalSRFO to provide the first beta RF transmit signal FBTX via the firstbeta harmonic filter 74. In another communications mode, such as asecond beta half-duplex transmit mode, a second beta saturated mode, ora second beta non-linear mode, the beta RF switch 72 is configured toforward the second RF output signal SRFO to provide the second beta RFtransmit signal SBTX via the second beta harmonic filter 78. In analternate communications mode, such as a beta full-duplex mode or a betalinear mode, the beta RF switch 72 is configured to forward the secondRF output signal SRFO to provide any of a third beta RF transmit signalTBTX through the Q^(TH) beta RF transmit signal QBTX. When a specific RFband is selected, the beta RF switch 72 may be configured to provide acorresponding selected one of the third beta RF transmit signal TBTXthrough the Q^(TH) beta RF transmit signal QBTX. The first alphaharmonic filter 70 or the second alpha harmonic filter 76 may be used tofilter out harmonics of an RF carrier in the first RF output signalFRFO. The first beta harmonic filter 74 or the second beta harmonicfilter 78 may be used to filter out harmonics of an RF carrier in thesecond RF output signal SRFO.

FIG. 10 is a graph showing a saturated load line 80 and a linear loadline 82 associated with the first RF PA 50 and the envelope power supplysignal EPS illustrated in FIG. 5 according to one embodiment of thefirst RF PA 50 and the envelope power supply signal EPS. The horizontalaxis of the graph represents an envelope power supply voltage VEPS ofthe envelope power supply signal EPS and the vertical axis of the graphrepresents an envelope power supply current IEPS of the envelope powersupply signal EPS. Characteristic curves 84 of an amplifying element(not shown) in the first RF PA 50 (FIG. 5) are overlaid onto the graphfor clarity. The saturated load line 80 has a saturated operating range86 and the linear load line 82 has a maximum linear operating range 88.The saturated load line 80 may be associated with operation of the firstRF PA 50 in a saturated manner and the linear load line 82 may beassociated with operation of the first RF PA 50 in a linear manner. Thelinear load line 82 is shifted from the saturated load line 80 by anoffset 90, which may represent the minimum increase in the envelopepower supply voltage VEPS needed to allow the first RF PA 50 to operatein a linear manner. It should be noted that further increases of theenvelope power supply voltage VEPS beyond the offset 90 may furtherincrease linearity of the first RF PA 50. Certain modulation modes,particularly those having high peak-to-average powers may need increasedlinearity for proper operation. The offset 90 may be determinedempirically. A similar relationship may exist between the envelope powersupply signal EPS and the second RF PA 54 (FIG. 5).

FIG. 11 is a graph showing a saturated operating characteristic 92associated with the first RF PA 50 and the envelope power supply signalEPS illustrated in FIG. 5 according to one embodiment of the first RF PA50 and the envelope power supply signal EPS. The horizontal axis of thegraph represents the envelope power supply voltage VEPS of the envelopepower supply signal EPS and the vertical axis of the graph represents anoutput power POUT from the first RF PA 50 (FIG. 5). The saturatedoperating characteristic 92 is indicative of saturated operation of thefirst RF PA 50 over multiple values of the envelope power supply voltageVEPS. Values of the output power POUT that correspond to the multiplevalues of the envelope power supply voltage VEPS may also correspond tomultiple magnitudes of the first RF output signal FRFO, which maycorrespond to multiple magnitudes of the first RF input signal FRFI.

FIG. 12 is a graph showing the saturated operating characteristic 92, alinear operating characteristic 94, a first modulation specificoperating characteristic 96, and a second modulation specific operatingcharacteristic 98 associated with the first RF PA 50 and the envelopepower supply signal EPS illustrated in FIG. 5 according to oneembodiment of the first RF PA 50 and the envelope power supply signalEPS. The horizontal axis of the graph represents the envelope powersupply voltage VEPS of the envelope power supply signal EPS and thevertical axis of the graph represents the output power POUT from thefirst RF PA 50 (FIG. 5).

The saturated operating characteristic 92 is indicative of saturatedoperation of the first RF PA 50 over multiple values of the envelopepower supply voltage VEPS. The linear operating characteristic 94 isindicative of linear operation of the first RF PA 50 over multiplevalues of the envelope power supply voltage VEPS. The linear operatingcharacteristic 94 may be shifted from the saturated operatingcharacteristic 92 by the offset 90, which may represent the minimumapproximate increase in the envelope power supply voltage VEPS needed toprovide linear operating behavior in the first RF PA 50 (FIG. 5). Ingeneral, the offset 90 is based on differences between the saturatedoperating characteristic 92 and the linear operating characteristic 94.

The first modulation specific operating characteristic 96 may beindicative of operation of the first RF PA 50 (FIG. 5) over multiplevalues of the envelope power supply voltage VEPS using a firstcommunications mode. The first modulation specific operatingcharacteristic 96 may be shifted from the linear operatingcharacteristic 94 by a first modulation back-off 100, which mayrepresent the minimum approximate decrease in the output power POUTneeded to meet linearity requirements mandated by the firstcommunications mode. In general, the first modulation back-off 100 isbased on differences between the linear operating characteristic 94 andthe first modulation specific operating characteristic 96.

The second modulation specific operating characteristic 98 may beindicative of operation of the first RF PA 50 (FIG. 5) over multiplevalues of the envelope power supply voltage VEPS using a secondcommunications mode. The second modulation specific operatingcharacteristic 98 may be shifted from the linear operatingcharacteristic 94 by a second modulation back-off 102, which mayrepresent the minimum approximate decrease in the output power POUTneeded to meet linearity requirements mandated by the secondcommunications mode. In general, the second modulation back-off 102 isbased on differences between the linear operating characteristic 94 andthe second modulation specific operating characteristic 98. Generically,a modulation back-off is associated with a selected communications modeand is based on differences between the linear operating characteristic94 and a modulation specific operating characteristic that is associatedwith the selected communications mode.

In an exemplary embodiment of the first RF PA 50 (FIG. 5), the firstmodulation specific operating characteristic 96 is associated with acommunications mode that provides voice communications using a WCDMAprotocol and the second modulation specific operating characteristic 98is associated with a communications mode that provides datacommunications using a WCDMA protocol. The voice signal has a 3.4decibel (dB) peak-to-average power and the data signal has a 6.8 dBpeak-to-average power. As a result, both signals require modulationback-off to meet linearity requirements. However, since the data signalhas a larger peak-to-average power than the voice signal, the datasignal requires a larger modulation back-off to meet linearityrequirements. As such, the first modulation back-off 100 is about 3.2 dBand the second modulation back-off 102 is about 7.2 dB. The values givenare exemplary only and are not intended to limit the scope of theinvention in any way.

Values of the output power POUT that correspond to the multiple valuesof the envelope power supply voltage VEPS may also correspond tomultiple magnitudes of the first RF output signal FRFO, which maycorrespond to multiple magnitudes of the first RF input signal FRFI.

Two embodiments of the RF communications circuitry 26 illustrated inFIG. 3 are presented. In a first embodiment of the RF communicationscircuitry 26, the envelope power supply signal EPS is restricted basedon a desired magnitude of the first RF input signal FRFI. In a secondembodiment of the RF communications circuitry 26, the first RF inputsignal FRFI is limited based on a magnitude of the envelope power supplysignal EPS.

In the first embodiment of the RF communications circuitry 26 (FIG. 3),the RF PA circuitry 30 (FIG. 3) is associated with a first saturationoperating constraint. The RF PA circuitry 30 receives and amplifies thefirst RF input signal FRFI to provide the first RF output signal FRFOand receives the envelope power supply signal EPS, which provides powerfor amplification. The RF modulation and control circuitry 28 (FIG. 3)selects one of multiple communications modes and determines a desiredmagnitude of the first RF input signal FRFI. The RF modulation andcontrol circuitry 28 determines a minimum allowable magnitude of theenvelope power supply signal EPS based on the first saturation operatingconstraint, the selected communications mode, and the desired magnitudeof the first RF input signal FRFI. The selected communications mode isassociated with any offset 90 (FIG. 12) or modulation back-off needed toprovide the linearity required for the selected communications mode. TheRF modulation and control circuitry 28 restricts a magnitude of theenvelope power supply signal EPS based on the minimum allowablemagnitude of the envelope power supply signal EPS by not allowing themagnitude of the envelope power supply signal EPS to drop below theminimum allowable magnitude of the envelope power supply signal EPS. TheRF modulation and control circuitry 28 provides the first RF inputsignal FRFI, which has approximately the desired magnitude of the firstRF input signal FRFI and has RF modulation corresponding to the selectedcommunications mode. The first saturation operating constraint may bebased on first calibration data, which may be obtained during saturatedoperation of a calibration RF PA at different envelope power supplylevels. The calibration RF PA may be the first RF PA 50 (FIG. 5), thesecond RF PA 54 (FIG. 5), or a surrogate RF PA (not shown).

The desired magnitude of the first RF input signal FRFI may be based ona desired magnitude of the first RF output signal FRFO, which may bebased on a desired RF output power from the RF PA circuitry 30 (FIG. 3).The first saturation operating constraint may be further based on theoffset 90 (FIG. 12). Combining the first saturation operating constraintwith the offset 90 (FIG. 12), as needed, and any needed modulationback-off, such as the first modulation back-off 100 (FIG. 12) or thesecond modulation back-off 102 (FIG. 12)may provide adequate headroomfor the RF PA circuitry 30 (FIG. 3).

In the second embodiment of the RF communications circuitry 26 (FIG. 3),the RF PA circuitry 30 (FIG. 3) is associated with the first saturationoperating constraint. The RF PA circuitry 30 receives and amplifies thefirst RF input signal FRFI to provide the first RF output signal FRFOand receives the envelope power supply signal EPS, which provides powerfor amplification. The RF modulation and control circuitry 28 (FIG. 3)selects one of multiple communications modes. The RF modulation andcontrol circuitry 28 determines a maximum allowable magnitude of thefirst RF input signal FRFI based on the first saturation operatingconstraint, the selected communications mode, and a magnitude of theenvelope power supply signal EPS. The selected communications mode isassociated with any offset 90 (FIG. 12) or modulation back-off needed toprovide the linearity required for the selected communications mode. TheRF modulation and control circuitry 28 limits a magnitude of the firstRF input signal FRFI based on the maximum allowable magnitude of thefirst RF input signal FRFI by not allowing the magnitude of the first RFinput signal FRFI to exceed the maximum allowable magnitude of the firstRF input signal FRFI. The RF modulation and control circuitry 28provides the first RF input signal FRFI, which has RF modulationcorresponding to the selected communications mode. The first saturationoperating constraint may be based on first calibration data, which maybe obtained during saturated operation of a calibration RF PA atdifferent envelope power supply levels. The calibration RF PA may be thefirst RF PA 50 (FIG. 5), the second RF PA 54 (FIG. 5), or a surrogate RFPA (not shown). The maximum allowable magnitude of the first RF inputsignal FRFI may be based on a maximum allowable magnitude of the firstRF output signal FRFO, which may be based on a maximum RF output powerfrom the RF PA circuitry 30 (FIG. 3). The maximum RF output power may bebased on the first saturation operating constraint.

In one embodiment of the RF communications circuitry 26 (FIG. 5), thefirst RF PA 50 (FIG. 5) is associated with a first saturation operatingconstraint and the second RF PA 54 (FIG. 5) is associated with a secondsaturation operating constraint. When selected, the first RF PA 50 mayreceive and amplify the first RF input signal FRFI to provide the firstRF output signal FRFO and may receive the envelope power supply signalEPS, which may provide power for amplification to the first RF PA 50.When selected, the second RF PA 54 may receive and amplify the second RFinput signal SRFI to provide the second RF output signal SRFO and mayreceive the envelope power supply signal EPS, which may provide powerfor amplification to the second RF PA 54.

The RF modulation and control circuitry 28 (FIG. 5) may select eitherthe first RF PA 50 (FIG. 5) or the second RF PA 54 (FIG. 5) and mayselect one of multiple communications modes. When the first RF PA 50 isselected, the RF modulation and control circuitry 28 determines adesired magnitude of the first RF input signal FRFI. When the second RFPA 54 is selected, the RF modulation and control circuitry 28 determinesa desired magnitude of the second RF input signal SRFI. When the firstRF PA 50 is selected, the RF modulation and control circuitry 28determines a minimum allowable magnitude of the envelope power supplysignal EPS based on the first saturation operating constraint, theselected communications mode, and the desired magnitude of the first RFinput signal FRFI. The selected communications mode is associated withany offset 90 or modulation back-off needed to provide the linearityrequired for the selected communications mode. When the second RF PA 54is selected, the RF modulation and control circuitry 28 determines aminimum allowable magnitude of the envelope power supply signal EPSbased on the second saturation operating constraint, the selectedcommunications mode, and the desired magnitude of the second RF inputsignal SRFI.

The RF modulation and control circuitry 28 (FIG. 5) restricts amagnitude of the envelope power supply signal EPS based on the minimumallowable magnitude of the envelope power supply signal EPS by notallowing the magnitude of the envelope power supply signal EPS to dropbelow the minimum allowable magnitude of the envelope power supplysignal EPS. When the first RF PA 50 (FIG. 5) is selected, the RFmodulation and control circuitry 28 may provide the first RF inputsignal FRFI, which has approximately the desired magnitude of the firstRF input signal FRFI and has RF modulation corresponding to the selectedcommunications mode. When the second RF PA 54 (FIG. 5) is selected, theRF modulation and control circuitry 28 provides the second RF inputsignal SRFI, which has approximately the desired magnitude of the secondRF input signal SRFI and has RF modulation corresponding to the selectedcommunications mode. The first saturation operating constraint may beabout equal to the second saturation operating constraint. The firstsaturation operating constraint may be based on first calibration data,which may be obtained during saturated operation of a calibration RF PAat different envelope power supply levels. The calibration RF PA may bethe first RF PA 50 (FIG. 5), the second RF PA 54 (FIG. 5), or asurrogate RF PA (not shown). The second saturation operating constraintmay be based on second calibration data, which may be obtained duringsaturated operation of the second RF PA 54 at different envelope powersupply levels. The first RF PA 50 may be a highband RF PA and the secondRF PA 54 may be a lowband RF PA.

FIG. 13 shows a calibration configuration for obtaining the firstcalibration data, which may be acquired during saturated operation ofthe first RF PA 50 at different envelope power supply levels accordingto one embodiment of the present disclosure. The first calibration datais associated with a saturated operating characteristic of the first RFPA 50. Calibration circuitry 104 provides the first RF input signal FRFIand the envelope power supply signal EPS to the first RF PA 50. Thefirst RF PA 50 receives and amplifies the first RF input signal FRFI toprovide the first RF output signal FRFO to the calibration circuitry104. The envelope power supply signal EPS provides power foramplification to the first RF PA 50. The calibration circuitry 104provides the first RF input signal FRFI and the envelope power supplysignal EPS as necessary for saturated operation of the first RF PA 50 atdifferent envelope power supply levels. The calibration circuitry 104obtains the first calibration data via the first RF output signal FRFO.

FIG. 14 shows a calibration configuration for obtaining the firstcalibration data and the second calibration data according to analternate embodiment of the present disclosure. The first calibrationdata may be acquired during saturated operation of the first RF PA 50 atdifferent envelope power supply levels and the second calibration datamay be acquired during saturated operation of the second RF PA 54 atdifferent envelope power supply levels. The first calibration data isassociated with a saturated operating characteristic of the first RF PA50 and the second calibration data is associated with a saturatedoperating characteristic of the second RF PA 54.

The calibration circuitry 104 provides the first RF input signal FRFIand the envelope power supply signal EPS to the first RF PA 50 andprovides the second RF input signal SRFI and the envelope power supplysignal EPS to the second RF PA 54. The first RF PA 50 receives andamplifies the first RF input signal FRFI to provide the first RF outputsignal FRFO to the calibration circuitry 104. The envelope power supplysignal EPS provides power for amplification to the first RF PA 50. Thesecond RF PA 54 receives and amplifies the second RF input signal SRFIto provide the second RF output signal SRFO to the calibration circuitry104. The envelope power supply signal EPS provides power foramplification to the second RF PA 54. The calibration circuitry 104provides the first RF input signal FRFI and the envelope power supplysignal EPS as necessary for saturated operation of the first RF PA 50 atdifferent envelope power supply levels. The calibration circuitry 104obtains the first calibration data via the first RF output signal FRFO.Similarly, the calibration circuitry 104 provides the second RF inputsignal SRFI and the envelope power supply signal EPS as necessary forsaturated operation of the second RF PA 54 at different envelope powersupply levels. The calibration circuitry 104 obtains the secondcalibration data via the second RF output signal SRFO.

FIG. 15 shows a calibration configuration for obtaining the firstcalibration data and the second calibration data according to anadditional embodiment of the present disclosure. The calibrationconfiguration illustrated in FIG. 15 includes the RF communicationscircuitry 26 illustrated in FIG. 7 and the calibration circuitry 104.The calibration circuitry 104 includes calibration circuitry DCI 106which is coupled to the transceiver circuitry 34, the RF PA circuitry30, the DC-DC converter 32, and the front-end aggregation circuitry 36via the digital communications bus 66. Further, the calibrationcircuitry 104 is coupled to the antenna port AP of the front-endaggregation circuitry 36. The first calibration data may be acquiredduring saturated operation of the first RF PA 50 at different envelopepower supply levels and the second calibration data may be acquiredduring saturated operation of the second RF PA 54 at different envelopepower supply levels. The first calibration data is associated with thesaturated operating characteristic of the first RF PA 50 and the secondcalibration data. The second calibration data is associated with thesaturated operating characteristic of the second RF PA 54.

The calibration circuitry 104 provides saturated operation of the firstRF PA 50 and the second RF PA 54 by controlling the first RF inputsignal FRFI and the second RF input signal SRFI using the transceivercircuitry 34 via the control circuitry DCI 58. Further, the calibrationcircuitry 104 provides saturated operation of the first RF PA 50 and thesecond RF PA 54 by controlling the envelope power supply signal EPSusing the DC-DC converter 32 via the DC-DC converter DCI 62. Thecalibration circuitry 104 controls the RF PA circuitry 30 via the PA DCI60 and controls the front-end aggregation circuitry 36 via theaggregation circuitry DCI 64 to route either the first RF output signalFRFO or the second RF output signal SRFO, as necessary, to thecalibration circuitry 104 through the antenna port AP.

The calibration circuitry 104 controls the first RF input signal FRFIand the envelope power supply signal EPS as necessary for saturatedoperation of the first RF PA 50 at different envelope power supplylevels. The calibration circuitry 104 obtains the first calibration datavia the first RF output signal FRFO. Similarly, the calibrationcircuitry 104 controls the second RF input signal SRFI and the envelopepower supply signal EPS as necessary for saturated operation of thesecond RF PA 54 at different envelope power supply levels. Thecalibration circuitry 104 obtains the second calibration data via thesecond RF output signal SRFO.

FIG. 16 illustrates a process for obtaining the first calibration dataaccording to one embodiment of the present disclosure. The process maybe associated any of the calibration configurations illustrated in FIG.13, FIG. 14, or FIG. 15. The process begins by providing calibrationequipment (Step 200), such as the calibration circuitry 104. The processcontinues by selecting one of a calibration mode and a normal operationmode (Step 202). This step may be performed by the calibration equipmentor by other circuitry. The process continues by providing the first RFPA 50, which during the normal operation mode may receive and amplifythe first RF input signal FRFI to provide the first RF output signalFRFO; receive the envelope power supply signal EPS, which may providepower for amplification to the first RF PA 50; and operate in one ofmultiple communications modes, such that the envelope power supplysignal EPS has a minimum allowable magnitude based on a first saturatedoperating constraint, the one of the multiple communications modes, anda desired magnitude of the first RF input signal FRFI (Step 204).

The process continues by during the calibration mode, providing theenvelope power supply signal EPS to the first RF PA 50 (Step 206),followed by during the calibration mode, providing a first group ofmagnitudes of the envelope power supply signal EPS (Step 208), which isfollowed by during the calibration mode, providing the first RF inputsignal FRFI, such that the first RF PA 50 operates in saturation (Step210). In general, the input power to the first RF PA 50 may becontrolled by controlling the first RF input signal FRFI, such that thefirst RF PA 50 remains sufficiently saturated while the envelope powersupply signal EPS is varied. The envelope power supply signal EPS may bevaried though its operating range. Further, the envelope power supplysignal EPS may be swept through its operating range. The first RF inputsignal FRFI may be a constant power continuous wave (CW) signal, amodulated GMSK signal, or some other signal that keeps the first RF PA50 in sufficient saturation.

The process continues by during the calibration mode, receiving andamplifying the first RF input signal FRFI to provide the first RF outputsignal FRFO (Step 212). This step may typically be performed by thefirst RF PA 50. The process completes by during the calibration mode,measuring a magnitude of the first RF output signal FRFO at each of thefirst group of magnitudes of the envelope power supply signal EPS toobtain the first calibration data, which is based on a first saturatedoperating characteristic of the first RF PA 50 (Step 214). In analternate embodiment of the process for obtaining the first calibrationdata, the process includes the additional step of during the calibrationmode, providing the RF PA circuitry 30, the DC-DC converter 32, thetransceiver circuitry 34, and the front-end aggregation circuitry 36having the antenna port AP, such that the measuring the magnitude of thefirst RF output signal FRFO is via the antenna port AP. In an additionalembodiment of the process for obtaining the first calibration data, anyof the process steps may be omitted, additional process steps may beadded, or both.

FIG. 17 illustrates a process for obtaining the second calibration dataaccording to one embodiment of the present disclosure. The process maybe associated either of the calibration configurations illustrated inFIG. 14 or FIG. 15. The process begins by providing the second RF PA 54(Step 216). During the normal operation mode, the second RF PA 54 mayreceive and amplify the second RF input signal SRFI to provide thesecond RF output signal SRFO; receive the envelope power supply signalEPS, which may provide power for amplification to the second RF PA 54;and operate in one of multiple communications modes, such that theenvelope power supply signal EPS has a minimum allowable magnitude basedon a second saturated operating constraint, the one of the multiplecommunications modes, and a desired magnitude of the second RF inputsignal SRFI.

The process continues by during the calibration mode, providing theenvelope power supply signal EPS to the second RF PA 54 (Step 218),followed by during the calibration mode, providing a second group ofmagnitude of the envelope power supply signal EPS (Step 220), which isfollowed by during the calibration mode, providing the second RF inputsignal SRFI, such that the second RF PA 54 operates in saturation (Step222). In general, the input power to the second RF PA 54 may becontrolled by controlling the second RF input signal SRFI, such that thesecond RF PA 54 remains sufficiently saturated while the envelope powersupply signal EPS is varied. The envelope power supply signal EPS may bevaried though its operating range. Further, the envelope power supplysignal EPS may be swept through its operating range. The second RF inputsignal SRFI may be a constant power CW signal, a modulated GMSK signal,or some other signal that keeps the second RF PA 54 in sufficientsaturation.

The process continues by during the calibration mode, receiving andamplifying the second RF input signal SRFI to provide the second RFoutput signal SRFO (Step 224). This step may typically be performed bythe second RF PA 54. The process completes by during the calibrationmode, measuring a magnitude of the second RF output signal SRFO at eachof the second group of magnitudes of the envelope power supply signalEPS to obtain the second calibration data, which is based on a secondsaturated operating characteristic of the second RF PA 54 (Step 226). Inan alternate embodiment of the process for obtaining the secondcalibration data, the process includes the additional step of during thecalibration mode, providing the RF PA circuitry 30, the DC-DC converter32, the transceiver circuitry 34, and the front-end aggregationcircuitry 36 having the antenna port AP, such that the measuring themagnitude of the second RF output signal SRFO is via the antenna portAP. In an additional embodiment of the process for obtaining the secondcalibration data, any of the process steps may be omitted, additionalprocess steps may be added, or both.

FIG. 18 illustrates a process for determining the offset 90 (FIG. 12)and a modulation back-off, such as the first modulation back-off 100(FIG. 12) or the second modulation back-off 102 (FIG. 12), of acalibration RF PA, such as the first RF PA 50, the second RF PA 54, or asurrogate RF PA. The process begins by obtaining calibration data basedon a saturated operating characteristic of the calibration RF PA, suchthat the saturated operating characteristic relates magnitudes of theenvelope power supply signal EPS, which provides power for amplificationto the calibration RF PA, to magnitudes of RF output power POUT from thecalibration RF PA during saturated operation of the calibration RF PA(Step 300). The process continues by determining an offset 90 based ondifferences between the saturated operating characteristic and a linearoperating characteristic of the calibration RF PA, such that the linearoperating characteristic relates magnitudes of the envelope power supplysignal EPS to magnitudes of the RF output power POUT during linearoperation of the calibration RF PA (Step 302). The process completes bydetermining a modulation back-off for each of multiple modulation modesof the calibration RF PA, such that each modulation back-off is based ondifferences between the linear operating characteristic and an operatingcharacteristic of the calibration RF PA that provides a desired outputresponse from the calibration RF PA (Step 304).

In an alternate embodiment of the process for obtaining the offset 90and the modulation back-off, the desired output response from thecalibration RF PA provides a desired output frequency spectrum responsefrom the calibration RF PA. In another embodiment of the process forobtaining the offset 90 and the modulation back-off, the desired outputresponse from the calibration RF PA provides a desired linearityresponse from the calibration RF PA. In a further embodiment of theprocess for obtaining the offset 90 and the modulation back-off, thedesired output response from the calibration RF PA provides a desirederror vector magnitude (EVM) response from the calibration RF PA. In anadditional embodiment of the process for obtaining the offset 90 and themodulation back-off, any of the process steps may be omitted, additionalprocess steps may be added, or both.

Some of the circuitry previously described may use discrete circuitry,integrated circuitry, programmable circuitry, non-volatile circuitry,volatile circuitry, software executing instructions on computinghardware, firmware executing instructions on computing hardware, thelike, or any combination thereof. The computing hardware may includemainframes, micro-processors, micro-controllers, DSPs, the like, or anycombination thereof.

None of the embodiments of the present disclosure are intended to limitthe scope of any other embodiment of the present disclosure. Any or allof any embodiment of the present disclosure may be combined with any orall of any other embodiment of the present disclosure to create newembodiments of the present disclosure.

Those skilled in the art will recognize improvements and modificationsto the preferred embodiments of the present disclosure. All suchimprovements and modifications are considered within the scope of theconcepts disclosed herein and the claims that follow.

What is claimed is:
 1. A method comprising: providing calibrationequipment; selecting one of a calibration mode and a normal operationmode; providing a first radio frequency (RF) power amplifier (PA)adapted to during the normal operation mode: receive and amplify a firstRF input signal to provide a first RF output signal; receive an envelopepower supply signal, which provides power for amplification to the firstRF PA; and operate in one of a plurality of communications modes, suchthat the envelope power supply signal has a minimum allowable magnitudebased on a first saturation operating constraint, the one of theplurality of communications modes, and a desired magnitude of the firstRF input signal; during the calibration mode, providing the envelopepower supply signal to the first RF PA; during the calibration mode,providing a first plurality of magnitudes of the envelope power supplysignal; during the calibration mode, providing the first RF inputsignal, such that the first RF PA operates in saturation; during thecalibration mode, receiving and amplifying the first RF input signal toprovide the first RF output signal; and during the calibration mode,measuring a magnitude of the first RF output signal at each of the firstplurality of magnitudes of the envelope supply signal to obtain firstcalibration data, which is based on a first saturated operatingcharacteristic of the first RF PA.
 2. The method of claim 1 furthercomprising during the calibration mode, providing RF PA circuitry, adirect current (DC)-DC converter, transceiver circuitry, and front-endaggregation circuitry having an antenna port, such that the measuringthe magnitude of the first RF output signal is via the antenna port. 3.The method of claim 1 further comprising: providing a second RF PA;during the calibration mode, providing the envelope power supply signalto the second RF PA; during the calibration mode, providing a secondplurality of magnitudes of the envelope power supply signal; during thecalibration mode, providing the second RF input signal, such that thesecond RF PA operates in saturation; during the calibration mode,receiving and amplifying the second RF input signal to provide thesecond RF output signal; and during the calibration mode, measuring amagnitude of the second RF output signal at each of the second pluralityof magnitudes of the envelope supply signal to obtain second calibrationdata, which is based on a second saturated operating characteristic ofthe second RF PA.
 4. The method of claim 3 further comprising during thecalibration mode, providing RF PA circuitry, a direct current (DC)-DCconverter, transceiver circuitry, and front-end aggregation circuitryhaving an antenna port, such that the measuring the magnitude of thefirst RF output signal is via the antenna port and measuring themagnitude of the second RF output signal is via the antenna port.
 5. Themethod of claim 3 wherein during the normal operation mode, the secondRF PA is adapted to: receive and amplify a second RF input signal toprovide a second RF output signal; receive the envelope power supplysignal, which provides power for amplification to the second RF PA; andoperate in one of a plurality of communications modes, such that theenvelope power supply signal has a minimum allowable magnitude based ona second saturation operating constraint, the one of the plurality ofcommunications modes, and a desired magnitude of the second RF inputsignal.